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Re: st: Stratified Sampling


From   "Eric G. Wruck" <ewruck@econalytics.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Stratified Sampling
Date   Fri, 9 Sep 2005 20:04:09 -0400

Of course there is some theory.  The one time I made use of stratified sampling I relied on William G. Cochran's "Sampling Techniques" (1977) published by Wiley & Sons.  Basically, you want to sample in proportion to the variance of the variable of interest.  In this way your sample is likely to be more informative.

Good luck,

Eric

 

>Hi,
>
>I am teaching a sophomore social statistics course.
>I've been covering sampling, especially stratified
>sampling this week.
>
>The students need some assistance in explaining the
>weighting procedures associated with disproportionate
>stratified sampling.  How can I demonstrate this in a
>class with a concrete example.
>
>Also, is there any guidelines as to how to oversample
>a particular stratum?  Assuming i have 2 groups (males
>are 20% and Females=80%). If I am drawing a sample of
>100 students - it means I would end up with 20 males
>and 80 females.  If i need to oversample the males,
>what values should i chose - 30, 40, 50? - is the
>choice really arbitrary or is guided by theory or
>calculations?
>
>I will appreciate your thoughts on this.
>
>Regards, YC



-- 

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       Eric G. Wruck
       Econalytics
       2535 Sherwood Road
       Columbus, OH  43209

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       cell:    614.330.8846
       eFax:    614.573.6639
       eMail:   ewruck@econalytics.com
       website: http://www.econalytics.com

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